The present invention relates to a heat exchanging device for effecting heat exchange between two fluids of different temperatures.
The prerequisite with an electronic apparatus of the kind consuming great power is that heat generated in the apparatus be radiated to the outside in order to prevent inside temperature from rising. The elevation of temperature inside the apparatus would render the operation of the individual device constituting circuitry unstable and would result in the malfunction and failure of the apparatus. To meet such a requirement, a cooling fan has customarily been mounted on the apparatus in order to introduce cool air from the outside while discharging hot air from the inside, i.e., to replace inside air and outside air.
However, the problem with the cooling fan is that dust is introduced into the apparatus together with outside air. Particularly, dust containing, e.g., conductive metal powder is apt to bring about a critical trouble in the apparatus. In light of this, a filter is also mounted on the apparatus in order to filter out dust. This, however, brings about another problem that the filter must be replaced and cleaned periodically; otherwise, dust would stop up the filter and would thereby lower the efficiency of the fan. Replacing and cleaning the filter periodically is problematic from the function and management standpoint. Moreover, when the apparatus is adapted for an outdoor application, rain and water are likely to enter the apparatus. Therefore, the apparatus cannot be situated outdoor alone.
Japanese Patent Laid-Open Publication No. 3-1095, for example, discloses a heat exchanging device capable of effecting heat exchange without replacing fluids. This kind of heat exchanging device, however, has a problem that passageways for fluids are too narrow and complicated to implement a high flow rate, failing to guarantee a sufficient amount of heat exchange for a unit time.